Your body-language will give you away even with black hair and glasses (not to mention that people don't tend to wear sunglasses as much as in the West.)

As to people pointing and saying "gaijin", it'll happen sometimes, although mostly by elementary school kids. It's annoying sometimes, but like anything you'll get used to it, especially since it's almost never said with malice, but rather with surprise.

And if you can't handle getting laughed at by little kids, well then...